Before troubleshoot,please check if your power supply has switched to corret voltage. please note that ,there is a 110V/220V switch in power supply, switch it to correct position according to residential voltage in your country.

(1)Problem: X axis motor cannot move even in the manual control mode.

1.1 First check the connection of the X axis motor, see if it was wrongly connected. If it’s correct connected, then swap the X axis motor with the Y axis. If the X motor still cannot turn then the X motor is dead.Similarly you can swap the motor driver or the motor wire to see if any of them is dead or not.

1.2 Check the directions of the step driver. The wrong direction will damage the board!
A4988:

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DRV8825：

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1.3 Check the subdivision of the step motor.
So if you use A4988 and 1/16 step, you should plug in the caps like this:

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And for 8825:

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1.4 Check the voltage of the motor driver and the motor connector.
Measure the voltage of the driver board, normally the value should be 0.8V-1.2V, you can put the red probe of multimeter on the potentiometer, and put the black one on the GND.
If the voltage is too low or too high, the step motor will not work stable. It will lose steps or vibrates, sometimes too hot. You can rotate the potentiometer on the driver to adjust the voltage to about 1.0V and see it if works.NOTE: the voltage between VDD and GND on the driver board of GT2560 is 5V, and on the board GTM32 it is 3.3V.

driver voltage

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( 2) Z axis won’t move on Prusa I3 X

Problem: the two Z motors were making a grinding noise, when trying to change the Z-axis location through the Repetier host program. The Z axis did not move. This was the behavior immediately after the assembly has been completed.

Possible reason: the Z motor is more complex than the others, it has two motors. The left and right sides of the Z axis have to be at exactly the same height. It has to carry a heavy load against gravity.
Refer to the link here to check your printer.http://www.geeetech.com/forum/viewtopic ... 917(thanks dolphi for sharing!)

I had the same problem but worse....It would work fine for a bit then start groaning partially thru the print...so frustrating...so I did some checking...I played with the driver board adjustment...turning the voltage up and down...nope wasnt that....I put several commands to a motor to make it move a ways and I wiggled the wire connector on the motor...BINGO....motor would groan...change directions on its own....So I pulled each wire from the white holder and pinched the connector together with a pair of my wifes tweezers...put it together and zip tied the wire to the motor....have not heard that horrible sound again.....did it to all the motors....

Check it out...send a move command and wiggle the connector....good luck

The Z axis stepper motor bearings are carrying a substantial load for such little bearings. The resulting loading is a problem. I overcame this problem by modifying the design. I fitted two rs608 ball bearings to the upper ends of both Z axis threaded rods and nuts above the bearings to take the full weight of the load. Now the universal couplings on the Z axis motors are under tension (not compression) forces and the stepper motors are as a consequence carring no weight at all!!. Both Z axis motors now work like a dream. See image below. Note: the bearing housings are not fixed to the acrylic but float and thus are self aligning. The housings are just PVC electrical conduit whose purpose is to ensure that the bearing centre doesn't come into contact with the acrylic parts of the printer. I skimmed the inside diameter of the conduit to fit the bearings against a PVC conduit shoulder for this purpose.

Load support bearings for Z axis rods. Note the nut screwed to the threaded rod supporting the weight through the bearing?

IMG_20151028_081217 (480x640).jpg (121.24 KiB) Viewed 51291 times

Also, the Z axis threaded rods are a poor fit in the universal couplings. This causes ungainly movement and a further unnecessary workload onto the universal couplings with a resulting knock down effect of increasing the load on the tiny Z axis motor bearings still further. To rectify this problem I machined about 6 mm of one end of both Z axis threaded rods and fitted sleeves to both threaded rods, each with holes for the grub screws to go through to lock the universal coupling directly to the rods. See image below.

I am just setting up my printer. I also ran into a problem with the X-Axis frozen earlier today. I could hear the motor attempting to turn, but there was no movement. I had already known that the print bracket had been too tight with too little clearance for the belt to move freely though it. I figured that there was too much cross tension on on the belt. I took a Dremel and widen the space where the belt travels through the bracket. That cured that particular problem.

But I am on here tonight because of some additional problems that i have run into. I'll post them separately.

My suggestion...Before any mechanical assembly, and to have any electronic adjustment...
Roll your soft rod on a flat desk...If it wobble will rolling, you have to fix it or get new rod.
Second roll your beiring over the intire length, they should not grind or stop.You should not
Feel the rod twist in your hands while the beiring slide over...

I found while attempting to resolve wobble and jam, that greetech rod supplyer are masking the
Imperfection by making chrome deposite over the rod to mask cracked rod. Mine where doing all
The above...But when I polished them all all the beiring jam, the rod where cracked. The stainless extrusion
Coild be seing on the whole length and twisting...Greetech is sending me new rod...

I guess that I should have relied long before now. The problem turned out to be that belt was rubbing against itself in the X-Carriage bracket. A new X-Carriage bracket with more clearance cured this problem.

If your Z movement is binding up and if Z threaded rods are straight, try loosening both Z motors mounting screws and the mounting screws on the brass fitting (Z axis nut Part No. 16)on the threaded rod. (You may have to loosen the linear bearing (Part No. 41) mounting screws also if that is causing the binding) Then check for full movement of the Z axis. This lets the threaded rods and guides and motors find their own non-binding center. Then tighten all the mounting screws back up in a crisscross fashion taking care not to move the parts from where they found their center.

I'm having a slightly different problem with my Z-axis motors.
Only one motor will run. If I swap the cables, then the other motor will run.
So the motors are good.
I have tried new driver boards and the problem remains.
The X and Y work fine.
Thanks

Slayer456 wrote:I'm having a slightly different problem with my Z-axis motors.
Only one motor will run. If I swap the cables, then the other motor will run.
So the motors are good.
I have tried new driver boards and the problem remains.
The X and Y work fine.
Thanks